All things modern.
Have a look at these taps that I encountered at London Heathrow. The silver thing on the left is the water tap. For your information, it’s a touch-free tap, you place your hands underneath and the water starts to flow. So now here is a trick question: How do you use the soap?
Humans learn by collecting throughout their lives a set of rules that define what is expected to happen for every action. Thus when confronted with a problem, the human brain searches through past scenarios which bear similarity to the one presently before it. In this way, past knowledge is brought to bear on the problem in order to solve it.
Consider the two silver projections in the picture, one of which we already know it the water tap, and works by simply placing hands underneath the tap. Once hands are wet, we require soap, and since the two look so similar, one places hands under the second silver projection expecting a blob of soap to be ejected onto the hands. But nothing happens. So one tries the one at the adjacent sink, then another, and eventually concludes that none of them are working and proceeds to (yuck) just use water.
Based on past experience of a few seconds ago (the water tap) it is reasonable to conclude that the soap dispenser also works in the same way. However when no soap is dispensed in this way, it is also reasonable to conclude that the dispenser is faulty. There are no signs to indicate that there is any other way to obtain soap.
This design is therefore a good example of a design that has not taken into account the human factors that affect how products are used. In this case, the result was that I received no soap, a minor consequence unless I thereafter contracted a bad case of e-coli. However if this same design method was used in the design of aircraft flight indicators or the controls of a medical device the results can be fatal.
Designers, never neglect human factors!
P.S. you push the end of the silver projection for soap.